The switching efficiency of the two modes at two wavelengths 1537nm and 1558nm are ?98.4% and ?98.7%, respectively. The proposed multiple OAM mode switch has potential applications in the future hybrid multi-dimensional multiplexing optical fiber communication systems.We present a gear-shaped plasmonic nano-structure with structural tunability and high RI sensitivity. New tunable geometric parameters of the gear-tooth give further flexibility for design. By using FDTD method, the reflection spectrum of the structure is theoretically analyzed with analyte RI in the range of 1.0 to 1.44. The best achieved sensitivity is- 1044 nm/RIU for our proposed structure. The resonance wavelength of the structure is independent of the polarization angle for large number of teeth. The structure can be used to design tunable sensors for biomedical and chemical applications.We propose and investigate the performance of integrated photonic isolators based on non-reciprocal mode conversion facilitated by unidirectional, traveling acoustic waves. A triply-guided waveguide system on-chip, comprising two optical modes and an electrically-driven acoustic mode, facilitates the non-reciprocal mode conversion and is combined with spatial mode filters to create the isolator. The co-guided and co-traveling arrangement enables isolation with no additional optical loss, without magnetic-optic materials, and with low power consumption. The approach is theoretically evaluated with simulations predicting over 20 dB of isolation and 2.6 dB of insertion loss with a 370 GHz optical bandwidth and 1 cm device length. The isolator uses only 1 mW of electrical drive power, an improvement of 1-3 orders of magnitude over the state of the art. The electronic drive and lack of magneto-optic materials suggest the potential for straightforward integration with drive circuits, including in monolithic CMOS electronic-photonic platforms, enabling a fully contained 'black box' optical isolator with two optical ports and DC electrical power.We demonstrated a narrowband eye-safe intracavity Raman laser by incorporating a fused silica etalon into the fundamental resonator. The KGd(WO4)2 (KGW) Raman laser was pumped by an actively Q-switched NdYLF laser at 1314 nm. Thanks to the KGW bi-axial properties, two distinct eye-safe Raman lasers operating at 1461 and 1490 nm were obtained separately by rotation of the KGW crystal. At an optimized pulse repetition frequency of 4 kHz, the maximum average output powers of 3.6 and 4.0 W were achieved with the peak powers up to approximately 330 and 480 kW, respectively. The eye-safe Stokes emissions were narrow linewidth (?0.05 nm FWHM; measurement limited) and near diffraction limited (M2? less then ?1.4). The powerful narrowband eye-safe Raman lasers are of interest for applications as diverse as laser range finding, scanning lidar and remote sensing.To improve signal detection in a turbid medium, we propose temporally encoded single shot polarimetric integral imaging. An optical signal is temporally encoded using gold coded sequences and transmitted through a turbid medium. The encoded signals are captured as a sequence of elemental images by two orthogonal polarized image sensor arrays. Polarimetric and polarization difference imaging are used to suppress the partially polarized and unpolarized background noise such that only the polarized ballistic signal photons are captured at the sensor. Multidimensional integral imaging is used to obtain 4D reconstructed data, and multidimensional nonlinear correlation is performed on the reconstructed data to detect the optical signal. We compare the effectiveness of the proposed polarimetric underwater optical signal detection approach to conventional (non-polarimetric) integral imaging-based and 2D imaging-based signal detection systems. The underwater signal detection capabilities are measured through performance metrics such as receiver operating characteristic (ROC) curves, the area under the curve (AUC), and the number of detection errors. https://www.selleckchem.com/products/cerdulatinib.html Furthermore, statistical measures, including the Kullback-Leibler divergence, signal-to-noise ratio (SNR), and peak-to-correlation energy (PCE), are also calculated to show the improved performance of the proposed system. Our experimental results show that the proposed polarimetric integral-imaging approach significantly outperforms the conventional imaging-based methods. To the best of our knowledge, this is the first report on temporally encoded single shot polarimetric integral imaging for signal detection in turbid water.True-time delays are important building blocks in modern radio frequency systems that can be implemented using integrated microwave photonics, enabling higher carrier frequencies, improved bandwidths, and a reduction in size, weight, and power. Stimulated Brillouin scattering (SBS) offers optically-induced continuously tunable delays and is thus ideal for applications that require programmable reconfiguration but previous approaches have been limited by large SBS gain requirements. Here, we overcome this limitation by using radio-frequency interferometry to enhance the Brillouin-induced delay applied to the optical sidebands that carry RF signals, while controlling the phase of the optical carrier with integrated silicon nitride microring resonators. We report a delay tunability over 600?ps exploiting an enhancement factor of 30, over a bandwidth of 1?GHz using less than 1?dB of Brillouin gain utilizing a photonic chip architecture based on Brillouin scattering and microring resonators.We demonstrate an on-chip coherent mode scrambling demultiplexer for polarization multiplexed few mode signals. The device has been fabricated in the standard silicon-on-insulator platform. The mode demultiplexer consists of an array of 2D grating couplers for dual polarization few mode fiber-to-chip coupling and optical hybrids realized by 4×4 MMIs. The array of perfect vertical 2D grating couplers allows us an efficient fiber-to-chip coupling with experimental peak coupling efficiencies of -5.2?dB and -9.0?dB at 1570?nm for LP01 and LP11 modes, respectively, while simulated coupling efficiencies at 1550?nm are -3.6?dB and -3.3?dB for LP01 and LP11, respectively. We successfully performed a back-to-back three LP modes division multiplexing transmission experiment with single polarization 32 Gbaud QPSK signals using the fabricated mode demultiplexer relying on offline MIMO DSP techniques.